This invention relates to the control of chilled or warmed water flowing to a plurality of individually controlled temperature zones within a building. In particular, this invention relates to the balancing of the demand for the chilled or warmed water among the individually controlled temperature zones.
Controlling the flow of chilled or warmed water to a plurality of individual zones in a home or office building is well known. The amount of water flowing to a given zone depends on that zone's needs as measured by a thermostat sensing the temperature of the space or zone to be heated or cooled. When the temperature of the space deviates from a predetermined set point, a valve controlling the flow of water to the zone is moved to a more open position allowing a greater volume of chilled or warmed water to flow through one or more heat exchangers in the zoned space. Conversely, as the temperature of the space approaches the set point, the valve is moved to a more closed position so as to decrease the volume of water flowing through the heat exchangers in the zoned space.
The above flow control does not allow for adjustments in valve position for other than temperature difference. As a result, some zones may reach their respective set points quicker than other zones. This will be especially true in those instances where the measurement of change of temperature in a zone is substantially greater than the other zones.